56 Ba Barium 137.33
Alkaline-earth metal
Barium 钡
[Xe] 6s²
- Period 6
- Group 2
- Block s
- Solid
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s²
Orbital diagram (valence)
6s ↑↓
- Electrons per shell
- 2, 8, 18, 18, 8, 2
- Unpaired electrons
- 0
- Zeff (Slater)
- 2.85
Properties
- Atomic weight
- 137.33
- Electronegativity (Pauling)
- 0.89
- First ionization energy
- 502.9 kJ/mol
- Electron affinity
- no data
- Covalent radius
- 215 pm
- van der Waals radius
- 268 pm
- Melting point
- 1000 K
- Boiling point
- 2170 K
- Density
- 3.62 g/cm³
- Melting / boiling point
- 726.9 °C / 1896.8 °C
- Common oxidation states
- +2
- Discovered
- 1808
Emission spectrum
Barium flame · green
Barium in the course
The lessons that discuss this element most (ranked by mentions).
- Reactions in aqueous solution Reactions and stoichiometry
- Hydrogen and the s-block The main-group elements
- The solubility product Precipitation and complex ions
- Activities and the salt effect Precipitation and complex ions
- Gravimetric analysis Titrimetric and gravimetric analysis
- Proton transfer: acids, bases and pH Acids and bases
Lab experiments with Barium
Periodic trend
Group 2
Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).